Polycyclic scents

ABSTRACT

New polycyclic Diels-Alder adducts which are formed on reaction of 8-vinyl-tricyclo-[5,2,1,0 2 ,6 ]-dec-8-ene or 8-hydroxy-8-vinyl-tricyclo-[5,2,1,0 2 ,6 ]-decane with alkenes or alkynes having one or two activating substituents, e.g., --COOH, --COOCH 3 , --COOC 2  H 5 , --CHO, --COCH 3 , --COC 2  H 5  or --CN. They have green, fresh, fruity and in some cases woody odors with long-lasting tenacity and/or fixing properties. They can be used as constituents of perfumes and of compositions for perfuming body care products, detergents and other consumer products.

The subject application is a divisional application of Ser. No. 708,994,which was filed in the U.S. on July 26, 1976 and is now allowed and isU.S. Pat. No. 4,076,748 issued Feb. 28, 1978.

The present invention relates to Diels-Alder adducts of the generalformula I ##STR1## where R¹ and R² are --H or --CH₃, or R¹ and R²together are a further bond between the carbon atoms on which they arepresent, and X and Y are each --CH₂ OH, --CH(OH)--CH₃, --COOH, --COOCH₃,--COOC₂ H₅, --CHO, --CO--CH₃, --CO--C₂ H₅ or --CN, or X and Y togetherare --CO--O--CO--, or one of X or Y is --H or CH₃ and the other has oneof the above meanings.

The new polycyclic Diels-Alder adducts are distinguished by valuablescent characteristics. They have green, fresh, fruity and in some caseswoody odors with long-lasting tenacity and/or fixing properties. Theymay be used as constituents of perfumes and of compositions forperfuming body care products, e.g. soaps, shampoos and hair lotions,detergents and other consumer products. Furthermore, they may be usedfor flavoring foodstuffs and tobacco.

The present invention further relates to a process for the manufactureof the new compounds of the formula I, wherein the new8-vinyltricyclo-[5,2,1,0²,6 ]-dec-8-ene of the formula II ##STR2## issubjected to a Diels-Alder reaction, by conventional methods, with adienophile of the general formula III ##STR3## where R¹ and R² are --Hor --CH₃ or R¹ and R² together are a further bond between the carbonatoms on which they are present and X and Y are each --COOH, --COOCH₃,--COOC₂ H₅, --CHO, --COCH₃, --COC₂ H₅ or --CN, or X and Y together are--CO--O--CO--, or one of X and Y is --H or --CH₃ and the other has oneof the above meanings.

The new Diels-Alder adducts of the formula I, in which R¹ and R² are --Hor --CH₃ and one of X or Y is --CH₂ OH or --CH(OH)--CH₃ and the other isH, are obtained by reducing the corresponding oxo compounds byconventional methods.

8-Vinyl-tricyclo-[5,2,1,0²,6 ]-dec-8-ene, required as a startingcompound, can be manufactured by a simple conventional method, byelimination of water from 8-vinyl-tricyclo-[5,2,1,0²,6 ]-decan-8-ol,which in turn can be obtained by reacting tricyclo-[5,2,1,0²,6]-decan-8-one, which is readily accessible, with a vinyl-magnesiumhalide by the Grignard method. Instead of the diene II,8-vinyl-tricyclo-[5,2,1,0²,6 ]-decan-8-ol can be used as the startingmaterial, but this requires more severe reaction conditions, e.g. highertemperatures and/or acid catalysts, and the yields are thereforefrequently less.

Suitable dienophiles of the formula III are:

(a) Alkenes having only one activating substituent, i.e. compounds ofthe formula III, where R¹ and R² are --H or --CH₃, one of X or Y is--COOH, --COOCH₃, --COOC₂ H₅, --CHO, --CO--CH₃, --CO--C₂ H₅ or --CN andthe other X or Y is --H, i.e. mono-α,β-unsaturated aldehydes, ketones,nitriles, carboxylic acids or carboxylic acid esters. Examples which maybe mentioned are acrolein, methacrolein, crotonaldehyde, methyl vinylketone, pent-2-en-4-one, acrylonitrile, methacrylonitrile,crotononitrile, acrylic acid, methacrylic acid, crotonic acid and themethyl esters and ethyl esters of the said 3 acids. The above aldehydes,ketones and nitriles are preferred.

(b) Alkenes with two activating substituents, i.e. compounds of theformula III, where R¹ and R² are --H or --CH₃, especially --H, and X andY are each --COOH, --COOCH₃, --COOC₂ H₅, --CHO, --CO--CH₃, --CO--C₂ H₅or --CN, or X and Y together are --CO--O--CO--. Examples which may bementioned are dimethyl fumarate, diethyl fumarate and maleic anhydride.

(c) Alkylenes with only one activating substituent, i.e. compounds ofthe formula III, where R¹ and R² together are a further bond between thecarbon atoms on which they are present, one of X or Y is --COOH,--COOCH₃, --COOC₂ H₅, --CHO, --CO--CH₃, --CO--C₂ H₅ or --CN and theother is --H or --CH₃. Examples which may be mentioned arepropionaldehyde (propynal), butyn-2-al, propionic acid, tetrolic acid(butyn-2-oic acid), and the methyl esters and ethyl esters of the saidacids.

(d) Alkynes with two activating substituents, i.e. compounds of theformula III, where R¹ and R² together are a further bond between thecarbon atoms on which they are present and X and Y are each --COOH,--COOCH₃, --COOC₂ H₅, --CHO, --CO--CH₃, --CO--C₂ H₅ or --CN. Exampleswhich may be mentioned are acetylenedicarboxylic acid and its methyl andethyl esters.

The dienophiles of the formula III are, in general, known and commercialcompounds.

Preferably, the alkenes with only one actuating substituent, describedunder (a), are used as dienophiles of the formula III.

In general, the Diels-Alder reaction is carried out by bringing amixture of 8-vinyl-tricyclo-[5,2,1,0²,6 ]-dec-8-ene (II), the dienophileof the formula III and, if appropriate, an inert solvent, to from 0 to150° C., preferably from 30 to 80° C., for the length of the reactiontime. The latter is from about 1 to 200 hours, depending on the natureof the dienophile. The dienophile is in general used in from about 0.5to 10 molar amount, preferably in from about 2 to 5 molar amount, basedon II.

To avoid possible resinification reactions, a small amount, i.e. fromabout 10 to 100 mg per mole of II, of a conventional stabilizer forDiels-Alder reactions, e.g. hydroquinone, is generally added to thereaction mixture.

The reaction may be carried out in the absence of solvents or in aninert solvent.

Examples of inert solvents which can be used are aliphatic hydrocarbons,e.g. pentane, hexane, cyclohexane and hydrocarbon fractions, aromatichydrocarbons, e.g. benzene, toluene or xylene, chlorohydrocarbons, e.g.methylene chloride, chloroform or chlorobenzene, ethers, e.g. diethylether, dipropyl ether, diisopropyl ether, tetrahydrofuran and anisole,alcohols, e.g. methanol, ethanol, propanol, isopropanol andcyclohexanol, ketones, e.g. acetone, methyl ethyl ketone and methylisopropyl ketone, amides, e.g. dimethylformamide, dimethylacetamide andhexamethylphosphotriamide or nitro compounds, e.g. nitromethane andnitrobenzene, or mixtures of the said solvents.

The reaction is either carried out at atmospheric pressure or under theautogenic pressure of the reactants in closed reaction vessels.

The reaction mixture is worked up by conventional methods, e.g. bydistillation.

Regarding further details of Diels-Alder reactions, reference may bemade to R. Sauer, Angew. Chem. 79 (1967), 77-94.

The Diels-Alder adducts are in general obtained as mixtures of differentisomers. When using unsymmetrical olefins of the formula III, 8stereoisomeric Diels-Alder adducts are possible, depending on the stericcourse of the addition reaction. The dienophile can attack "meta" or"ortho" to the C₉ of the diene of the formula II, "exo" or "endo" andfrom above or from below. The general rules of the Diels-Alder reactionand analogous examples with vinyl cyclohexenes or vinyl-bicylenes (seeA. S. Onishchenko "Diene Synthesis", Israel Program for ScientificTranslation, Jerusalem 1964, pages 410-445, especially pages 410-413 andpages 423-425) lead to the expectation that the main product would bethe "ortho-endo" isomer, i.e. in the case of acrolein the isomers##STR4## with the attack "from below" in the former case and "fromabove" in the latter. A prediction of the actual attack is difficult,given the complicated stereochemistry of the diene, and is decisivelydependent on the exo/endo configuration of the 5-membered ring. Ifsymmetrical olefins and alkynes are used as dienophiles of the formulaIII, the number of possible stereoisomers is less.

The stereoselectivity of the reaction can be increased by using very lowreaction temperatures and/or by adding catalytic amounts of Lewis acids,e.g. BF₃, AlCl₃, ZnCl₂ and the like (l.c., especially page 84).

If the reaction is carried out in the presence of catalytic amounts of aLewis acid such as AlCl₃, BF₃, SnCl₄ or ZnCl₂, the procedure followed isthat described above, but at lower temperatures, i.e. at from about -80to +20° C., preferably from -40 to 0° C. The amount of catalyst is from0.1 to 10%, preferably from 0.5 to 5%, based on II employed.

Carbonyl compounds can be reduced to the alcohols in accordance withnumerous standard processes, e.g. by catalytic hydrogenation, byreduction with metals or metal hydrides or by electrochemical orphotochemical reduction. Regarding further details, reference may bemade to S. Patai, "The Chemistry of the Hydroxyl Group", IntersciencePublishers 1971, pages 231-243. Example 3 describes the reduction of acarbonyl compound with a metal hydride (NaBH₄).

The new polycyclic Diels-Alder adducts are distinguished by valuablescent properties. They have green, fresh, fruity and in some cases woodyscents with long-lasting tenacity. Furthermore, they possess fixingproperties. Accordingly, they can be used as constituents of perfumesand of compositions for perfuming body care products, e.g. soaps,shampoos and hair lotions, detergents and other consumer products. Thescent depends somewhat on the stereochemistry (exo/endo ratio) of thetricyclo-[5,2,1,0²,6 ]-decan-8-one employed, but in general it issatisfactory to use the adducts obtained from the commercial ketone.

EXAMPLE

A solution of 8.0 g (0.05 mole) of 8-vinyl-tricyclo-[5,2,1,0²,6]-dec-8-ene, 10.6 g (0.2 mole) of acrylonitrile, 50 ml of toluene and 10mg of hydroquinone is heated at 80° C. for 12 hours. The reactionmixture is then cooled, washed with twice 30 ml of water, concentratedand distilled. 8.1 g (corresponding to 76% of theory) of an 80 : 20mixture of nitriles pass over at from 125 to 128° C./0.2 mm Hg. From theanalytical and spectroscopic data, the main product probably has theformula I, where R¹, R² and Y are --H and X is --CN.

n_(D) ²⁵ : 1.5325.

Scent: fresh, flowery, slightly fruity (lime), good tenacity.

What we claim is:
 1. A Diels-Alder adduct of the general formula I##STR5## where R¹ and R² are independently --H or --CH₃, or R¹ and R²together are a further bond between the carbon atoms on which they arepresent, and X and Y are each independently --CN or one of X and Y is--H or --CH₃ and the other has the above meaning.
 2. A Diels-Alderadduct of the general formula I ##STR6## where R¹ and R² areindependently --H or --CH₃, one of X and Y is --CN and the other is --H.